LARGE SPONTANEOUS VOLUME MAGNETOSTRICTION AND PRESSURE EFFECTS ON THEMAGNETIC-PROPERTIES OF AMORPHOUS CE-FE ALLOYS

The thermal expansion anomaly, the effects of pressure and hydrogenati on on the magnetization and the Curie temperature have been investigat ed in order to discuss the magnetovolume effects in the amorphous CexF e100-x alloys prepared by high-rate DC sputtering. These amorphous all oys have a large spontaneous volume magnetostriction which increases w ith decreasing x. The pressure effects on the magnetization, the spin freezing temperature and the Curie temperature are significant. The ma gnetization M varies linearly with the square of temperature T-2 in th e ferromagnetic state. The hydrogenation increases markedly both the C urie temperature and the magnetization of the amorphous CeFe2 alloy. H owever, no huge coercive force related to the random magnetic anisotro py has been confirmed at 4.2 K against the expectation based on a vale nce change of the Ce ion. For the amorphous CeFe2 alloy, the compressi bility estimated from the increases in the Curie temperature and the F e-Fe interatomic distance by hydrogenation, does not coincide with the experimental value obtained by Brillouin scattering. Therefore, the e xpansion due to hydrogenation is not regarded to be caused by a so-cal led negative hydrostatic pressure effect. (C) 1997 Elsevier Science S. A.